In templates used on userpages, it is sometimes important to determine whether it is a userpage of an unregistered user (IP address) or a registered one. Currently the following hack is used to do that:
{{#ifeq:{{lc:{{PAGENAME}}}}|{{uc:{{PAGENAME}}}}|IP|not IP}}
This tests if uppercase and lowercase of the pagename are equal. As IP-userpages have only digits and dots in them, they are detected correct. Most usernames contain letters, and those are detected correct as well. However, there are some false positive cases, if the username does not contain any letters (User:123 for example).
Therefor this is not a good solution of the problem, it'd be much nicer if ParserFunctions offered a test like {{#ip:<string>}} which returns true if it is an IP address and nothing if it is not.
Version: unspecified
Severity: enhancement